This invention relates to apparatus for collecting tissue, primarily from human beings, for use in uterine cancer screening and endometrial monitoring of patients. Generally, such apparatus includes a curette with a tissue-scraping spoon or the like at one end thereof, which includes a tissue-receiving opening communicating with a passageway extending through the curette and making communication with a housing from which the curette extends. The housing also includes an outlet to be connected to a suction pump which creates a negative pressure, which draws the scraped tissue through the curette and into the housing interior. A screen is placed in the path of flow of the tissue in the housing, which screen collects the tissue. The curette commonly has a suction release opening which removes suction from the end of the curette until the operator closes the hole to establish effective suction at the scraping spoon location at the time when tissue collection is desired. After the tissue is collected by the screen, it is removed from the screen and then examined by a pathologist.
Tissue collection apparatus as described has been heretofore manufactured in a variety of ways. U.S. Pat. No. 3,224,343 to Molomut et al., discloses what is referred to as a cell collection unit having a housing serving as both a handle and a tissue-collecting, filter screen containing housing. The housing is comprised primarily of two parts, one part constituting a curette supporting part which has an enlarged hub or the like at one end having a short internally threaded enlarged portion which receives the externally threaded shank of the other housing part which includes a central passageway communicating between the shank exterior and a rearwardly projecting spout which receives a tube extending to the suction pump. A disk-shaped filter and a washer are sandwiched in a small space between the shank of the latter housing part and the end wall of the short enlarged portion of the former housing part. While the disk-shaped screen described may be satisfactory for collecting a modest quantity of cells or tissue, the collecting area of the screen is so small as to be too small for most tissue collecting applications as described above.
U.S. Pat. No. 3,661,144 to Jensen et al shows a cell collecting apparatus which, while of a more complicated construction than that disclosed in said U.S. Pat. No. 3,224,343, is more adaptable for collecting greater quantities of tissue for examination. In the apparatus disclosed in this patent, the housing for the tissue collection screen is opaque or semi-transparent and comprises a large number of interfitting parts, making the construction thereof a relatively expensive one. Also, it utilizes a cylindrical tissue collection screen of much smaller diameter than the diameter of the housing therefor, the screen dividing the housing interior into an outer annular tissue inlet space and an inner annular space through which liquids and the like which pass through the screen are collected by the suction pump. The annular tissue collecting space on the outside of the screen limits the tissue collecting area of the screen, because of the relatively small diameter of the screen configuration. Also, the tissue collected on the outside of the screen is not readily visible through the housing and must be removed by picking it from the screen surface, which is a very tedious and time-consuming procedure.
U.S. Pat. No. 3,785,380 to Brumfield shows a blood sucker which filters surgical debris from the blood having a filter sleeve similar in construction to U.S. Pat. No. 3,661,144 to Jensen et al.
U.S. Pat. No. 3,889,657 to Baumgarten shows a uterine aspirating curette having a removable tapered or conical specimen collection basket. The material is collected on the inside of the basket and may be difficult to remove from the gauze or mesh basket lining. The basket casing may be made of substantially clear polymeric material to allow visual observation of the amount of collected tissue, but because the tissue is collected on the inside of the basket, it is not readily visible through the housing and basket. The curette has an exposed suction control opening in the basket casing, which casing also serves as the curette handle.
One of the objects of the present invention is to provide tissue collection apparatus which is of a much simpler and more inexpensive construction than that disclosed in the above mentioned patents, while providing a substantial tissue collection area much greater, for example, than that afforded by the disk-shaped screen configuration utilized in the apparatus of said U.S. Pat. No. 3,224,343 to Molomut et al.
A related object of the present invention is to provide tissue collection apparatus as described wherein the construction of the housing and the tissue collection screen contained therein is such as to provide for a very simple assembly procedure and which further permits the ready removal of the screen from the housing and the convenient removal of the tissue from the screen by the pathologist.
A further object of the present invention is to provide a tissue collection apparatus as described which is reliable and is not readily clogged before a maximum desired quantity of tissue is collected therein.